Loredana Postiglione

Behavior of SaOS-2 Cells Cultured on Different Titanium Surfaces

Surface properties may affect the clinical outcome of titanium dental implants. The aim of the present study was to investigate the effects of 3 different titanium surfaces—smooth (S), sandblasted (SB), and titanium plasma-sprayed (TPS)—on proliferation, differentiation, and apoptosis of human osteoblast-like cells, SaOS-2. Cell proliferation was significantly (p < 0.05) higher on the S surface, and synthesis of extracellular matrix proteins was more abundant on TPS and SB than on S surfaces. Analysis of integrin receptors showed a higher expression of α2, α5, αVβ3, and ß1 on TPS as compared with SB and S surfaces. An increase in alkaline phosphatase activity was detected only on SB and TPS surfaces. Analysis of cell apoptosis did not demonstrate any significant difference among the 3 different surfaces. The results indicate that titanium surface topography affects proliferation and differentiation of osteoblast-like SaOS-2 cells, suggesting that surface properties might be important for bone response around dental implants in vivo.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces the osteoblastic differentiation of the human osteosarcoma cell line SaOS-2.

The Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) is a hematopoietic growth factor that regulates the in vitro and in vivo proliferation and differentiation of hematopoietic cells through the interaction with a specific heterodimeric receptor complex (GM-CSFR), consisting of an a and a b chain with molecular weights of 80 and 120 KDa, respectively. We have studied the expression of the GM-CSFR (a chain) on the surface of the human osteosarcoma cell line SaOS-2 and the in vitro effects of different concentrations (10, 100, and 200 ng/ml) of GM-CSF on GM-CSFR expression and the biological activity of SaOS-2 cells. Our data show that SaOS-2 cells express GM-CSFR and that GM-CSF can down-regulate the expression of its own receptor on these cells. Furthermore, to evaluate the biological effects of GM-CSF on SaOS-2 cells, we have investigated cell proliferation and differentiation of these cells treated with different doses of the growth factor through: (1) a morphological analysis of typical osteoblast differentiation markers such as osteopontin and BSP-II; (2) measurement of alkaline phosphatase (ALP) activity; (3) production of bone ECM components (collagen I, fibronectin, tenascin, and laminin); (4) production of interleukin-6 (IL-6) and osteocalcin in the culture medium. The results show that the in vitro treatment of SaOS-2 cells with recombinant human GM-CSF causes a decreased cell proliferation and an increased production of osteopontin, BSP-II, ALP, IL-6, and most but not all ECM components. These findings suggest that GM-CSF can regulate proliferation and differentiation of osteoblast-like SaOS-2 cells and could also play an unexpected role in the maturation of bone tissue.

Different titanium surfaces modulate the bone phenotype of SaOS-2 osteoblast-like cells.

Commercially pure titanium implants presenting a relatively smooth, machined surface or a roughened endosseous surface show a large percentage of clinical success. Surface properties of dental implants seem to affect bone cells response. Implant topography appears to modulate cell growth and differentiation of osteoblasts affecting the bone healing around the titanium implant. The aim of the present study was to examine the effects of 1cm diameter and 1mm thick titanium disks on cellular morphology, adhesion and bone phenotypic expression of human osteoblast-like cells, SaOS-2. SaOS-2 cells were cultured on commercially 1 cm pure titanium disks with three different surface roughness: smooth (S), sandblasted (SB) and titanium plasma sprayed (TPS). Differences in the cellular morphology were found when they were grown on the three different surfaces. An uniform monolayer of cells recovered the S surface, while clusters of multilayered irregularly shaped cells were distributed on the rough SB and TPS surfaces. The adhesion of SaOS-2 cells, as measured after 3h of culture, was not affected by surface roughness. ECM components such as Collagen I (CoI), Fibronectin (FN), Vitronectin (VN) and Tenascin (TN) were secreted and organized only on the SB and TPS surfaces while they remained into the cytoplasm on the S surfaces. Osteopontin and BSP-II were largely detected on the SB and TPS surfaces, while only minimal production was observed on the S ones. These data show that titanium surface roughness affects bone differentiation of osteoblast like-cells, SaOS-2, indicating that surface properties may be able to modulate the osteoblast phenotype. These observations also suggest that the bone healing response around dental implants can be affected by surface topography.

Interleukin-6 release from peripheral mononuclear cells is associated to disease activity and treatment response in patients with lupus nephritis.

Sir, We read with great interest the article by De La Torre, et al. recently published in Lupus. The authors, through clinical and flow cytometric evaluations, demonstrate that there is an increased expression of interleukin-6 (IL-6) agonistic receptor gp130 on peripheral lymphocytes, drawn from patients with systemic lupus erythematosus (SLE). In addition, they interestingly report a significant association between gp130 expression and disease activity score, suggesting that gp130 could provide a useful tool for monitoring patients with SLE. In agreement with these findings, we report the results of a small longitudinal study, which we performed in patients with lupus nephritis, in order to evaluate the relationship among IL-6 release from peripheral blood mononuclear cells (PBMCs), proteinuria and disease activity. In this study, we demonstrate a strong correlation between IL-6 spontaneous release and both systemic and renal disease activity. Moreover, we supply evidence that an effective treatment results in decreasing clinical disease activity and IL-6 production by PBMCs. Fourteen patients (36.5 10.7 year, 12 women) affected by SLE, as defined by American Rheumatism Association criteria, with renal involvement (histological findings:WHO class III for six patients, class IV for five patients and class V for three patients) were enrolled. These patients underwent induction therapy with intravenousmethylprednisolone, followed by oral prednisone, and 6-monthly boluses of intravenous cyclophosphamide. After the induction, patients started the maintenance therapy with oral prednisone combined with either cyclosporine A (eight patients) or mycophenolate mofetil (six patients). A 12-month follow-up was performed. SLE disease activity index 2000 (SLEDAI-2K) was calculated every 3 months, as previously reported. Similarly, urine protein/creatinine (P/C) ratio and creatinine clearance on 24-h urine collection were calculated. IL-6 spontaneous production by PBMCs was evaluated before the initiation of the induction treatment (basal condition) and after 12 months. PBMCs were isolated from blood samples by lymphoprep gradient density centrifugation and were cultured for 24 h. At the end of the incubation period, cell-free supernatants were collected, and IL-6 concentration was evaluated by ELISA, as described elsewhere. IL-6 release by cultured PBMCs was significantly higher in basal condition when compared with posttreatment values (443.0 84.1 vs. 27.4 17.8 pg/mL; P< 0.001) (Figure 1A), whereas there was no significant difference in IL-6 levels between patients treated with mycophenolate or cyclosporine (20.2 10.5 vs. 32.7 20.9 pg/mL, ns). At 12month check-up, patients showed a significant decrease of both proteinuria and SLEDAI-2K, when compared with basal values (P/C ratio 1.76 1.25 vs. 0.69 0.38, P< 0.05, and 8.4 2.2 vs. 4.9 2.4, P< 0.01, respectively). Creatinine clearance did not significantly change (basal value 81.4 18.8 vs. 12-month value 81.3 17.2). IL-6 production resulted significantly associated to both SLEDAI-2K and P/C ratio (rs1⁄4 0.4180, P1⁄4 0.0002 and rs1⁄4 0.2670, P1⁄4 0.0049, respectively) (Figure 1B). However, this association could be due, at least in part, to the fact that an effective treatment may independently decrease both SLEDAI and IL-6 levels, acting as a confounding factor. High serum and urinary IL-6 levels have already been reported in lupus nephritis, but the relationship between IL-6 production and disease activity is still debated. Showing a close correlation between IL-6 spontaneous release and SLE activity, our data, in addition to those reported by De La Torre, could contribute to better define the important role of IL-6 activation in lupus nephritis. Longitudinal and bigger studies are required to confirm these findings and to discriminate the effects of different treatments on inflammatory status in patients with lupus nephritis.

Interleukin-10 and Interleukin-12 Modulation in Patients with Relapsing-Remitting Multiple Sclerosis on Therapy with Interferon-beta 1a: Differences in Responders and Non Responders

We examined the effects of interferon (IFN)beta-1a on interleukin (IL)-12p70 and IL-10 secretion in 27 Relapsing Remitting Multiple Sclerosis (RRMS) patients, divided in responders and non-responders. In responders, IFNbeta-1a does not change the IL-12p70 concentrations, but it leads to a remarkable increase in the IL-10 production. Besides, a high IL-10/IL-12 ratio is demonstrated during the first six months of therapy. In non-responders, there were not significant alterations in the cytokine profile. We suggest that IFNbeta-1a effect in RRMS patients could be explained by its modifying effect on cytokine pattern. Moreover, we propose a possible role of IL-10/ IL-12 ratio as a serum marker predictive of favorable clinical course.

Expression of GM-CSF receptor and “in vitro” effects of GM-CSF on human fibroblasts

In the present study the effects of Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) on fibroblast growth and activity have been studied. In this regard the AA have evaluated in primary cultures of human gengival normal fibroblasts (PG1 cells): a)-the expression of GM-CSF receptor (GM-CSFR) (alfa unit) on the cell surface; b)-the in vitro effects of different doses of GM-CSF on the GM-CSFR expression and on the proliferation and activity of fibroblasts. PG1 cells have been stimulated in vitro with different concentrations of GM-CSF (10, 50, 80, 100 and 150 ng/ml) using promonocytic cell line U937 as positive control for GM-CSFR expression. GM-CSFR was investigated by flow cytometry, with mouse monoclonal antibody (mAb) against the alfa chain of the human GM-CSFR and fluorescein-conjugated goat antimouse immunoglobulin G (IgG). At high GM-CSF concentration (80 ng/ml) the AA observed: 1)-A marked increase of GM-CSFR expression evaluated as fluorescence intensity (about three fold in respect to the controls); 2)-Maximal increase of PG1 cells proliferation. Moreover immunofluorescence on fibroblasts obtained from culture plates showed increased actin stress fibers and fibronectin production with low stimulation by GM-CSF, while higher concentration of this cytokine determined increased proliferation of cells, but a decreased formation of actine fibers and vinculin plaques. These results demonstrate: 1)-The presence of GM-CSFR on the surface of fibroblasts; 2)-The proliferation and the synthesis activity of these cells (in vitro) are modulated by different concentration of GM-CSF. We hypothesize that GM-CSF until 80 ng/ml can upregulate the expression of the receptor. Therefore, on the basis of previous findings of high serum levels of GM-CSF in course of scleroderma, a disease characterized by fibroblast hyperactivity, a possible role of this cytokine in the pathogenic process of this disease can be hypothesized.

Dietary calcium intake and serum vitamin D are major determinants of bone mass variations in women. A longitudinal study.

Background and aims: Bone mineral density (BMD) is one of the main determinants in the pathogenesis of fractures. However, data on factors predicting longitudinal variations in BMD are still limited and incomplete. Such data would be of great importance in order to better focus prevention strategies in both the clinical setting and at the population level. The aim of the study was to investigate the predictive value of both serological and questionnaire variables for bone mass variations in healthy women participating in a population-based longitudinal study carried out in Napoli, Italy. Methods: High completion rate (85.2%) and adequate sample size were obtained: 139 women (45 to 79 years of age) were examined at study entry and then again after two years (24±2 months) following the same protocol. They underwent medical examination, questionnaire, anthropometric measurements, blood sampling and urine collection. BMD was measured by dual energy X-ray absorptiometry (DEXA) at the lumbar spine (L1-L4) and femoral neck. Data analysis included calculation of the percent variation in BMD in the 2-year period. Longitudinal data underwent stepwise analysis for a global evaluation of mutual interactions between independent variables. Results and conclusions: Our findings indicate that dietary and serum calcium, and serum 25(OH)vitamin D are the only independent determinants of BMD variations at the lumbar and femoral level, respectively. While the pharmacological significance of calcium and vitamin D in the therapy of established osteoporosis is still controversial, the present longitudinal data evidence their role as essential nutrients in determining the natural history of BMD variations.

Calcium/calmodulin-dependent protein kinase II (CaMKII) phosphorylates Raf-1 at serine 338 and mediates Ras-stimulated Raf-1 activation.

The calcium/calmodulin-dependent kinase II (CaMKII) participates with Ras to Raf-1 activation, and it is necessary for activation of the extracellular signal-regulated kinase (ERK) by different factors in epithelial and mesenchimal cells. Raf-1 activation is a complex multistep process, and its maximal activation is achieved by phosphorylation at Y341 by Src and at S338 by other kinase/s. Although early data proposed the involvement of p21-activated kinase 3 (Pak3), the kinase phosphorylating S338 remains to be definitively identified. In this study, we verified the hypothesis that CaMKII phosphorylates Raf-1 at Ser338. To do so, we determined the role of CaMKII in Raf-1 and ERK activation by oncogenic Ras and other factors. Serum, fibronectin, SrcY527 and RasV12 activated CaMKII and ERK, at different extents. The inhibition of CaMKII attenuated Raf-1 and ERK activation by all these factors. CaMKII was also necessary for the phosphorylation of Raf-1 at S338 by serum, fibronectin and Ras. Conversely, inhibition of Pak3 activation by blocking phosphatidylinositol 3-kinase was ineffective. The direct phosphorylation of S338 Raf-1 by CaMKII was demonstrated in vitro by interaction of purified kinases. These results demonstrate that Ras activates CaMKII, which, in turn, phosphorylates Raf-1 at S338 and participates in ERK activation upon different stimuli.

The Plasminogen Activator System in Fibroblasts from Systemic Sclerosis

Systemic sclerosis (SSc) is characterized by excessive fibrosis throughout the body. There are two major subsets of SSc, diffuse cutaneous Systemic sclerosis (dSSc) and limited cutaneous Systemic sclerosis (ISSc). Fibroblasts play a key role in SSc. The expression and function of the urokinase (uPA)-mediated plasminogen activation (PA) system, a well-characterized system of serine-proteases involved in several pathological processes, has been investigated in SSc fibroblasts. The expression of the components of the PA system, including uPA, its type-1 and type-2 inhibitors (PAI-1 and PAI-2) and its receptor (uPAR), was examined by Western blot in fibroblasts from patients affected by limited and diffuse forms of SSc. uPA and PAI-1 secretion increased only in fibroblasts from ISSc lesions compared to normal fibroblasts. PAI-2 levels were decreased in fibroblasts from both SSc forms. Interestingly, fibroblasts from areas not adjacent to the lesions (not-affected) of the diffuse form showed reduced levels of PAI-1 and increased uPAR expression. Adhesion experiments showed reduced adherence to VN of fibroblasts from ISSc lesions and from non-affected areas of the diffuse form, as compared to normal controls. These results suggest a role for uPA and PAI-1 in the ISSc form, likely related to the activation of latent forms of cytokines and to the accumulation of ECM components, whereas a role for uPAR can be hypothesized in the evolvement of the diffuse form, based on its up-regulation in the non-affected areas.

Evidence That p-Cresol and IL-6 Are Adsorbed by the HFR Cartridge: Towards a New Strategy to Decrease Systemic Inflammation in Dialyzed Patients?

Introduction Hemodialysis (HD) and hemodiafiltration clear only with a low efficiency the plasma from interleukin-6 and p-cresol, two protein-bound uremic toxins associated with high cardiovascular risk in end stage renal disease. HFR Supra is a double-chamber hemodiafiltration system in which the ultrafiltrate returns to the patient after its regeneration through a resin cartridge that binds hydrophobic and protein-bound solutes. In the present study, we evaluated whether the HFR cartridge can also bind total p-cresol and IL-6 and remove them from the ultrafiltrate. Methods We compared the levels of IL-6 and p-cresol in ultrafiltrate samples collected at the inlet (UFin) and at the outlet (UFout) of the cartridge at the start or at the end of a 240 min HFR session in 12 inflamed chronic HD patients. The pro-inflammatory activity of the ultrafiltrate samples was also determined by evaluating the changes that they induced in IL-6 mRNA expression and protein release in peripheral blood mononuclear cells from 12 healthy volunteers. IL-6 and p-cresol circulating levels were also assessed in peripheral plasma blood samples collected before and after HFR and, for comparison, a control HD. Results p-Cresol and IL-6 were lower in UFout than in UFin both at the start and at the end of the HFR session, suggesting that they were retained by the cartridge. IL-6 mRNA expression and release were lower in PBMC incubated with UFout collected at the end than with UFin collected at the start of HFR, suggesting that passage through the cartridge reduced UF pro-inflammatory activity. Plasma total p-cresol decreased by about 53% after HFR, and 37% after HD. IL-6 circulating values were unmodified by either these dialysis procedures. Conclusions This study shows that the HFR-Supra cartridge retains total p-cresol and IL-6 in the ultrafiltrate and lowers plasma total p cresol but not IL-6 levels. Trial Registration ClinicalTrials.gov NCT01865773